Rotary drum type litter separating apparatus

ABSTRACT

In a rotary drum type litter separating apparatus including a cylindrical unit supported rotatably and having a peripheral surface formed in a mesh form as a part of the cylindrical unit, the cylindrical unit includes a bottomed part which closes one end of the cylindrical unit and a loaning/unloading port which opens the other end of the cylindrical unit, and a mesh part which is a detachable separate member is further attached to an outer periphery of the cylindrical unit. The litter separating apparatus is capable of separating various kinds of litter of different sizes from sand, thereby reliably collecting the litter. Moreover, the mesh part can be replaced easily. Thus, the workability is improved, and the man-hour is reduced. Such litter separating apparatus is capable of efficiently collecting various kinds and different sizes of litter.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present invention claims priority under 35 USC 119 based on Japanese Patent Application No. 2013-110404, filed on May 24, 2013. The entire subject matter of this priority document, including specification claims and drawings thereof, is incorporated by reference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a rotary drum type litter separating apparatus for collecting litter from a beach. More particularly, present invention relation to a litter separating apparatus having a plurality mesh parts of different mesh sizes for separating litter of various kinds and different sizes from sand.

2. Description of the Background Art

There is a known beach cleaner, which is used as an apparatus for collecting litter scattered on the sand ground of a sea beach or the like. An example of such beach cleaner is disclosed in the Japanese Patent Application Publication No. 2010-174518.

As described in the Japanese Patent Application Publication No. 2010-174518, a mesh of a drum type sieving member is usually formed of a single mesh. Thus, some types of litter may possibly pass through the mesh, which makes efficient litter separation impossible. Moreover, the drum type sieving member needs to be replaced with a different sieving member from one situation to another depending on the state of litter scattered on a sandy beach or the like, which makes litter collection time-consuming.

The present invention has been made to overcome the drawbacks of existing litter separating apparatus. Accordingly, it is one of the objects of the present invention is to provide a rotary drum type litter separating apparatus capable of efficiently collecting various kinds and different sizes of litter.

SUMMARY OF THE INVENTION

In order to achieve the above objects, the present invention according to a first aspect thereof provides a rotary drum type litter separating apparatus (10), including a cylindrical unit (50) supported rotatably and having a peripheral surface formed in a mesh form as a part of the cylindrical unit (50), in which the cylindrical unit (50) includes a bottomed part (56) which closes one end of the cylindrical unit (50) and a loading/unloading port (58 a) (also referred to as an opening) which opens the other end of the cylindrical unit (50), and a mesh part (100) which is a detachable separate member is further attached to an outer periphery of the cylindrical unit (50).

The present invention according to a second aspect thereof provides the rotary drum type litter separating apparatus (10), in which the mesh part (100) is attached to the cylindrical unit such that the mesh part wraps around the cylindrical unit (50), and opposite end sides of the mesh part (100) are connected by using hooks (102, 104) provided on the opposite end sides of the mesh part (100).

The present invention according to a third aspect thereof provides the rotary drum type litter separating apparatus (10), in which a mesh size of the mesh part (100) is finer than a mesh size of the peripheral surface of the cylindrical unit (50).

The present invention according to a fourth aspect thereof provides the rotary drum type litter separating apparatus (10), in which a rotational drive mechanism (52) is provided on the peripheral surface of the cylindrical unit (50) substantially around a central portion, specifically around the center, in a height direction of the cylindrical unit (50), and the mesh part (100) is detachably attached to a portion of an outer periphery of the cylindrical unit (50) excluding the rotational drive mechanism (52).

EFFECTS OF THE INVENTION

According to the first aspect of the present invention, the mesh part, which is a detachable separate member, is attached to the outer periphery of the cylindrical unit having a peripheral surface formed in a mesh form. Thus, by preparing in advance a plurality of mesh parts of different mesh sizes and attaching a mesh part suitable for the sizes of litter to be separated, it is possible to separate the litter of various kinds and different sizes from sand, thereby to reliably collect the litter. Moreover, the mesh part can be replaced easily. Thus, the workability is improved, and the man-hour is reduced.

According to the second aspect of the present invention, the mesh part is attached in such a way as to wrap the cylindrical unit, and the opposite end sides of the mesh part are connected by using the hooks provided on the opposite end sides of the mesh part. Thus, attachment and detachment of the mesh part is easy, and the man-hour for such operations is reduced.

According to the third aspect of the present invention, the mesh size of the mesh part is finer than the mesh size of the peripheral surface of the cylindrical unit. Thus, by changing the mesh size according to the sizes of litter to be separated, smaller sized pieces of litter can be collected.

According to the fourth aspect of the present invention, the rotational drive mechanism is arranged on the peripheral surface of the cylindrical unit substantially around the central portion in the height direction thereof, and the mesh part is detachably attached to the portion of the outer periphery of the cylindrical unit excluding the rotational drive mechanism. Thus, the width of the mesh part is small, and a storage space therefor can be slim.

For a more complete understanding of the present invention, the reader is referred to the following detailed description section, which should be read in conjunction with the accompanying drawings. Throughout the following detailed description and in the drawings, like numbers refer to like parts.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a litter separating apparatus (beach cleaner) according to an illustrative embodiment, and a towing vehicle, which tows the beach cleaner.

FIG. 2 is a view of the exterior of a rotary drum type litter separating apparatus shown in FIG. 1.

FIG. 3 is a view showing the relation between a rotational drive mechanism and a drive gear, and a planet gear shown in FIG. 1.

FIG. 4 is a schematic cross-sectional view of a cylindrical unit.

FIG. 5 is a perspective view of a metallic blade.

FIG. 6 is a view showing the metallic blade as seen from a direction X in FIG. 5.

FIG. 7 is a view showing the metallic blade as seen from a direction Y in FIG. 5.

FIG. 8 is a view of a main part of the litter separating apparatus as seen from an opening side.

FIG. 9 is a schematic view showing an example of a mesh part detachably attached to the outer periphery of the cylindrical unit shown in FIG. 4.

FIG. 10 is a schematic view showing another example of the mesh part detachably attached to the outer periphery of the cylindrical unit shown in FIG. 4.

FIG. 11 is an enlarged view of details of a part in FIG. 9.

FIG. 12 is an explanatory view of a method of attaching the mesh part.

FIG. 13 is a view showing a state where the mesh part is attached to the outer periphery of the cylindrical unit.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

An illustrative embodiment of the present invention will be described hereinafter in detail with reference to the accompanying drawings. Throughout this description, relative terms like “upper”, “lower”, “above”, “below”, “front”, “back”, and the like are used in reference to a vantage point of an operator of the vehicle, seated on the driver's seat and facing forward. It should be understood that these terms are used for purposes of illustration, and are not intended to limit the invention.

A rotary drum type litter separating apparatus according to the present invention will now be described in detail through an illustrative embodiment with reference to the accompanying drawings.

FIG. 1 is a perspective view showing a beach cleaner 12 including a rotary drum type litter separating apparatus 10 according to the illustrative embodiment. FIG. 1 also shows a towing vehicle 14 which tows the beach cleaner 12. FIG. 2 is a view of the exterior of the rotary drum type litter separating apparatus 10. Again, it may be noted that the terms front, rear, left, right, upper, and lower are based on directions seen from the driver of the towing vehicle 14, unless otherwise illustrated.

In the illustrative embodiment, an ATV (All-Terrain Vehicle), which is a saddle-ride type rough-terrain vehicle, is employed as the towing vehicle 14. The towing vehicle 14 includes: a pair of left and right front wheels 20 provided to a front lower portion of the body; a pair of left and right rear wheels 22 provided to a rear lower portion of the body; a pair of left and right front fenders 24 provided above the front wheels 20; and a pair of left and right rear fenders 26 provided above the rear wheels 22.

A handlebar 28 with which the front wheels 20 can be steered is provided above the front wheels 20. A front carrier 30 is arranged in front of the handlebar 28, and a seat 32 and a rear carrier 34 are arranged behind the handlebar 28.

Moreover, a pair of left and right step floors 36 for the driver seated on the seat 32 to rest his or her feet are formed between the handlebar 28 and the seat 32. The towing vehicle 14 rotates the rear wheels 22 with an engine (not shown) as a drive source.

The beach cleaner 12 includes: a tow frame 40 connectable to the towing vehicle 14; a pair of left and right wheels 42 provided on the lower side of a rear portion of the tow frame 40; and a support frame 44 which rotatably supports the rotary drum type litter separating apparatus (hereinafter, referred to as the litter separating apparatus) 10.

The litter separating apparatus 10 includes a cylindrical unit 50 having a peripheral surface formed in a mesh form as a part of the cylindrical unit 50. A rotational drive mechanism 52 is provided on the peripheral surface of the cylindrical unit 50 around the central portion of the cylindrical unit 50 in its height direction (the direction of its rotation axis). The rotational drive mechanism 52 includes a plurality of engagement portions 54 each formed in a pipe shape along the height direction of the peripheral surface of the cylindrical unit 50. The plurality of engagement portions 54 is attached in such that the engagement portions 54 from a loop around the outer periphery of the cylindrical unit 50. The cylindrical unit 50 includes a circular bottomed part 56 closing one end of the cylindrical unit 50, and an annular rim plate 58 having an opening 58 a (also referred to as a loading/unloading port 58 a) opening the other end of the cylindrical unit 50.

The cylindrical unit 50 includes: a plurality of pipes 60 each provided along the outer periphery of the cylindrical unit 50 in the height direction; and a mesh part (first mesh part) 62 attached to the inner side of the plurality of pipes 60 and wrapped in such a way as to cover the peripheral surface of the cylindrical unit 50. The peripheral surface of the cylindrical unit 50 is formed in a mesh form by the plurality of pipes 60 and the mesh part 62.

The opening 58 a functions as a loading port through which to load sand and litter mixed therein (hereinafter, referred to as mixed sand) into the cylindrical unit 50, and also functions as a removing port through which to remove litter remaining in the cylindrical unit 50.

The tow frame 40 rotatably supports an axel 64 connected to the pair of left and right wheels 42, and a drive gear 66 is connected to the axel 64. The support frame 44 is attached to the tow frame 40 and rotatably supports the litter separating apparatus 10. The litter separating apparatus 10 is supported on the support frame 44 with the opening 58 a on the left side and the bottomed part 56 on the right side.

The support frame 44 includes a front frame 68, a rear frame 70, a left frame 72, and a right frame 74 surrounding the litter separating apparatus 10 from the front, rear, left, and right sides. A roll 76 is rotatably attached to each of left and right portions of the front frame 68 and the rear frame 70. The litter separating apparatus 10 is rotatably supported by the four, front, rear, left, and right rolls 76. A plurality of contact plates 78 a, 78 b to be in contact with the rolls 76 are attached to a left end portion and a right end portion of the cylindrical unit 50. The contact plates 78 a, 78 b are attached to the opposite end sides of the cylindrical unit 50, respectively.

Two plate-shaped metallic blades 80 are provided inside the cylindrical unit 50, and each metallic blade 80 is provided extending from the opening 58 a to the bottomed part 56 (see FIG. 2). One edge of each metallic blade 80 in its width direction is provided along the inner peripheral surface of the cylindrical unit 50, while the other edge extends inward of the cylindrical unit 50. The width of the metallic blade 80 is set to become smaller from the opening 58 a of the cylindrical unit 50 toward the bottomed part 56 thereof. In other words, the metallic blade 80 is formed in such a way as to become wider toward the opening 58 a. The two metallic blades 80 are provided symmetrically with respect to the rotation axis of the cylindrical unit 50, and are provided obliquely with respect to the height direction of the cylindrical unit 50.

As shown in FIG. 3, a planet gear 82 is provided between the rotational drive mechanism 52 and the drive gear 66. The planet gear 82 meshes with the rotational drive mechanism 52 and the drive gear 66. Thus, as the towing vehicle 14 tows the beach cleaner 12, the wheels 42 of the beach cleaner 12 rotate, and the force of such rotation is transmitted to the rotational drive mechanism 52 through the drive gear 66 and the planet gear 82, thereby rotating the cylindrical unit 50 of the litter separating apparatus 10 toward the front of the towing vehicle 14.

Moreover, an operation lever 83 for manual engaging-disengaging (connecting-disconnecting) operations between the planet gear 82 and the rotational drive mechanism 52 and drive gear 66 is provided at a rear end portion of the beach cleaner 12. The planet gear 82 can be disconnected from and connected to the rotational drive mechanism 52 and the drive gear 66 by operating the operation lever 83. With the planet gear 82 disconnected from the rotational drive mechanism 52 and the drive gear 66, the cylindrical unit 50 of the litter separating apparatus 10 can be manually rotated even when the towing vehicle 14 is stopped.

A cover member 84, which covers the litter separating apparatus 10, is attached to the support frame 44 so as to prevent a person from accidentally touching the litter separating apparatus 10 while the litter separating apparatus 10, i.e. the cylindrical unit 50 is rotating.

FIG. 4 is a schematic cross-sectional view of the cylindrical unit 50. As the cylindrical unit 50 rotates, each metallic blade 80 scoops up mixed sand inside the cylindrical unit 50, and the mixed sand thus scooped up falls off the metallic blade 80 when the metallic blade 80 reaches a certain level. Since the peripheral surface of the cylindrical unit 50 is formed in a mesh form, the mixed sand can be efficiently sieved with the help of the falling of the mixed sand off the metallic blade 80. As a result, the sand falls through the cylindrical unit 50, and only the litter remains inside the cylindrical unit 50. In other words, the litter and the sand are separated. It may be noted that the sieving function (separating function) of the litter separating apparatus may be enhanced by causing the mixed sand to fall from a higher level.

A method of using the beach cleaner 12 will now be described briefly.

Here, the tow frame 40 is connected to the towing vehicle 14, and mixed sand is loaded through the opening 58 a of the cylindrical unit 50. Then, the towing vehicle 14 travels to rotate the cylindrical unit 50, so that the sand falls through the cylindrical unit 50 and the litter remains inside the cylindrical unit 50. Once the sand disappears from the inside of the cylindrical unit 50, the litter is collected through the opening 58 a. A litter collecting bag (not shown) for litter collection can be attached to the opening 58 a. Thus, the litter can be taken out through the opening 58 a, and the litter can be put into the litter collecting bag. Moreover, since the opening 58 a functions as a port through which to load mixed sand and also functions as a port through which to collect litter, the work efficiency is improved. Moreover, since the cylindrical unit 50 is rotated using the towing vehicle 14, there is no need to provide any drive source such as a motor to the beach cleaner 12. Thus, an inexpensive and convenient beach cleaner 12 can be provided.

FIG. 5 is a perspective view of each metallic blade 80. FIG. 6 shows the metallic blade 80 as seen from a direction X in FIG. 5. FIG. 7 shows the metallic blade 80 as seen from a direction Y in FIG. 5.

Each metallic blade 80 has a spiral shape defined by a quadric surface. Specifically, the metallic blade 80 has: a first flat portion 90; a first bent portion 92 connected to the first flat portion 90; a second flat portion 94 connected to the first bent portion 92; and a second bent portion 96 connected to the second flat portion 94.

The metallic blade 80 is arranged inside the cylindrical unit 50 such that the first flat portion 90 and the second bent portion 96 of the metallic blade 80 are disposed on the opening 58 a side and the bottomed part 56 side, respectively. The first bent portion 92 and the second bent portion 96 form the metallic blade 80 in a spiral shape (twisted shape) defined by a quadric surface, and provides variations in angle to the metallic blade 80, so that the first flat portion 90 and the second flat portion 94 appear differently from each other in angle and orientation (see FIG. 6).

The angle between the first flat portion 90 and the second flat portion 94 (smaller angle) as seen from the direction X in FIG. 5 is 58°. The angle between the second flat portion 94 and a tangent line of the second bent portion 96 at its tip (smaller angle) as seen from the direction Y in FIG. 5 is 59.9°. In other words, the blade 80 is configured such that the first flat portion 90 and the second flat portion 94 form an acute angel therebetween; and the second flat 94 portion and a tangent line of the second bent portion 96 at its tip also form an acute angle.

FIG. 8 is a view of the chief part of the litter separating apparatus 10 as seen from the opening 58 a side. As shown in FIG. 8, the angle between the first flat portion 90 and the circumferential direction of the cylindrical unit 50 (smaller angle) is set to be small, and the angle between the first flat portion 90 and the height direction of the cylindrical unit 50 (smaller angle) is set to be large.

On the other hand, the angle between the second flat portion 94 and the circumferential direction of the cylindrical unit 50 (smaller angle) is larger than that of the first flat portion 90, and the angle between the second flat portion 94 and the height direction of the cylindrical unit 50 (smaller angle) is smaller than that of the first flat portion 90. The first bent portion 92 is twisted in such a way as to bend from the first flat portion 90 to the second flat portion 94. Moreover, a length L1 of the first flat portion 90 and the first bent portion 92 in the height direction of the cylindrical unit 50 is smaller than a length L2 of the second flat portion 94 and the second bent portion 96.

With such construction, the first flat portion 90 and the first bent portion 92 of each metallic blade 80 can quickly move mixed sand near the opening 58 a of the cylindrical unit 50 to a slightly near side (the opening 58 a side) of a center area of the cylindrical unit 50 in the height direction. Accordingly, the mixed sand near the opening 58 a of the cylindrical unit 50 can be prevented from dropping out of the cylindrical unit 50 through the opening 58 a. The first flat portion 90 and the first bent portion 92 have a function of quickly moving litter.

Moreover, the second flat portion 94 and the second bent portion 96 of each metallic blade 80 can scoop up mixed sand and drop the scooped mixed sand from a higher level. Accordingly, the litter and the sand can be separated efficiently. The second flat portion 94 and the second bent portion 96 have a function of separating litter and sand.

Further, the width of each metallic blade 80 is set to become smaller from the opening 58 a of the cylindrical unit 50 toward the bottomed part 56 thereof. Thus, the amount of mixed sand scooped up by the metallic blade 80 is the largest at a portion of the second flat portion 94 on the opening 58 a side (a substantially center portion of the metallic blade 80), while the amount of mixed sand scooped up by the metallic blade 80 is not so large at a portion of the second flat portion 94 on the bottomed part 56 side and the second bent portion 96 (a portion of the metallic blade 80 on the bottomed part 56 side). Accordingly, mixed sand tends to gather around the center of the cylindrical unit 50 in the height direction, which in turn makes it possible to prevent litter from gathering on the far side, i.e. the bottomed part 56 side of the cylindrical unit 50. Hence, the litter can be collected easily. As described above, the litter separating apparatus 10 can separate sand and litter efficiently.

Here, the mesh size of the mesh part 62 is set with the mesh strength, rigidity, and other conditions taken into consideration. Thus, when litter is relatively small (when litter is smaller than the mesh size of the mesh part 62), the litter passes through the mesh part 62 and the litter falls through the cylindrical unit 50 along with the sand. Thus, sand and relatively small-sized litter cannot be separated.

For this reason, in the embodiment, a detachable mesh part (second mesh part) 100 is attached to the outer periphery of the cylindrical unit 50 to handle litter passing through the mesh part 62. The construction of detachable mesh part 100 will now be described.

FIG. 9 is a schematic view showing an example of the mesh part 100 detachably attached to the outer periphery of the cylindrical unit 50. The mesh part 100 is attached in such a way as to wrap around the outer periphery of the cylindrical unit 50. Specifically, portions of the outer periphery of the mesh potion 62 exposed to the outside. The mesh size of the mesh part 100 is finer (smaller) than the mesh size of the mesh part 62. The mesh part 100 is attached to portions of the outer periphery of the cylindrical unit 50 excluding the rotational drive mechanism 52. Specifically, the mesh part 100 includes a mesh part 100 a attached to the left of the rotational drive mechanism 52 and a mesh part 100 b attached to the right of the rotational drive mechanism 52. The widths of the mesh part 100 a and the mesh part 100 b are different but the other parts of their constructions are the same.

The description will only be provided for the mesh part 100 a.

Hooks 102, 104 are provided on one end side and the other end side of the mesh part 100 a in the longitudinal direction, respectively. There are provided two hooks 102 and two hooks 104 along the transverse direction (width direction) of the mesh part 100 a. It may be noted that there may instead be provided a single hook 102 a across the mesh part 100 a in the transverse direction as shown in FIG. 10.

Moreover, connection parts 106 for detachably connecting the one end side and the other end side of the mesh part 100 a are provided at the one end of the mesh part 100 a (see FIG. 11). Each connection part 106 is formed of a fastener 108 including a lever 108 a, and a substantially ring-shaped hanging part 110 provided to the lever 108 a.

As shown in FIG. 12, to attach the mesh part 100 a to the outer peripheral surface of the cylindrical unit 50, the hook 102 provided on the one end side of the mesh part 100 a is hung onto any one of the pipes 60 provided along the outer periphery of the cylindrical unit 50, and then the mesh part 100 a is wound around the cylindrical unit 50 once to wrap the outer peripheral surface of the cylindrical unit 50.

Then, the hanging part 110 is hung onto the hook 104 provided at the other end of the mesh part 100 a, and thereafter the lever 108 a of the fastener 108 is pushed toward the mesh part 100 a. As a result, the one end side and the other end side of the mesh part 100 a are connected. FIG. 13 shows a state where the mesh part 100 (mesh parts 100 a, 100 b) is attached to the outer periphery of the cylindrical unit 50.

It may be noted that although the hooks 104 and the connection parts 106 are used to connect the opposite end sides of the mesh part 100, the hooks 104 may simply be hung onto the mesh of the mesh part 100 to connect the opposite end sides of the mesh part 100. In this case, the connection parts 106 are not needed.

As described above, according to the above embodiment, the mesh part 100, which is a detachable separate member, is attached to the outer periphery of the cylindrical unit 50 having a peripheral surface formed in a mesh form. Thus, by preparing in advance a plurality of mesh parts 100 of different mesh sizes and attaching a mesh part 100 suitable for the sizes of litter to be separated, it is possible to separate various kinds of litter of different sizes from sand and reliably collect the litter. Moreover, the mesh part 100 can be replaced easily. Accordingly, the workability is improved, and the man-hour is reduced.

The mesh part 100 is attached in such a way as to wrap the cylindrical unit 50, and the opposite end sides of the mesh part 100 are connected by using the hooks 102, 104 provided on the opposite end sides of the mesh part 100. Thus, attachment and detachment of the mesh part 100 is easy, and the man-hour for such operations is reduced. The mesh size of the mesh part 100 is finer than the mesh size of the peripheral surface of the cylindrical unit 50 (the mesh size of the mesh part 62). Thus, smaller litter can be collected.

The opening 58 a functions as a port through which to load mixed sand and as a port through which to collect litter. Thus, the loading of mixed sand and the collecting of litter can be done at the same position, and the work efficiency is improved. The rotational drive mechanism 52 is provided on the peripheral surface of the cylindrical unit 50 around the center thereof in the height direction, and the mesh part 100 is detachably attached to the portions of the outer periphery of the cylindrical unit 50 excluding the rotational drive mechanism 52. Thus, the widths of the mesh parts 100 a, 100 b are small, and a storage space therefor can be slim.

It may be noted that although the mesh part 100 is formed of two members (mesh parts 100 a, 100 b) in the above embodiment, the mesh part 100 can be formed of a single member on condition that the rotational drive mechanism 52 is provided on an end portion of the mesh part 62 exposed to the outside at such a position as to abut one of the contact plates 78 a, 78 b, instead of being provided on the exposed portion of the mesh part 62 around the center in the height direction.

Moreover, a lid part that closes the opening 58 a of the cylindrical unit 50 may be attached when the litter separating apparatus 10 is used. In this way, mixed sand inside the cylindrical unit 50 can be reliably prevented from dropping out through the opening 58 a while the cylindrical unit 50 is rotated.

EXPLANATION OF THE REFERENCE NUMERALS

-   -   10 LITTER SEPARATING APPARATUS FOR BEACH CLEANER     -   12 BEACH CLEANER     -   14 TOWING VEHICLE     -   40 TOW FRAME     -   42 WHEEL p1 44 SUPPORT FRAME p1 50 CYLINDRICAL UNIT p1 52         ROTATIONAL DRIVE MECHANISM p1 54 ENGAGEMENT PORTION p1 56         BOTTOMED PART p1 58 RIM PLATE p1 58 a OPENING p1 60 PIPE p1 62,         100, 100 a, 100 b MESH PART p1 64 AXEL p1 66 DRIVE GEAR p1 80         METALLIC BLADE p1 102, 104 HOOK p1 106 CONNECTION PART p1 108         FASTENER p1 108 a LEVER p1 110 HANGING PART.

Although present invention has been described herein with respect to a number of specific illustrative embodiments, the foregoing description is intended to illustrate, rather than to limit the invention. Those skilled in the art will realize that many modifications of the illustrative embodiment could be made which would be operable. All such modifications, which are within the scope of the claims, are intended to be within the scope and spirit of the present invention. 

What is claimed is:
 1. A rotary drum type litter separating apparatus, comprising: a cylindrical unit having a peripheral surface thereof formed in a mesh form, said cylindrical unit including a bottomed part which closes one end of the cylindrical unit and a loading/unloading port which opens the other end of the cylindrical unit; and a mesh part attached to an outer periphery of the cylindrical unit; wherein said mesh part is a detachable separate member.
 2. The rotary drum type litter separating apparatus according to claim 1, wherein: said mesh part comprises hooks provided on opposite end sides thereof; the mesh part is arranged such that said mesh part wraps around the cylindrical unit; and the opposite end sides of the mesh part are connected by using said hooks.
 3. The rotary drum type litter separating apparatus according to claim 1, wherein a mesh size of the mesh part is finer than a mesh size of the peripheral surface of the cylindrical unit.
 4. The rotary drum type litter separating apparatus according to claim 2, wherein a mesh size of the mesh part is finer than a mesh size of the peripheral surface of the cylindrical unit.
 5. The rotary drum type litter separating apparatus according to claim 1, further comprising a rotational drive mechanism provided on the peripheral surface of the cylindrical unit around a central portion in a height direction of the cylindrical unit; wherein the mesh part is detachably attached to a portion of an outer periphery of the cylindrical unit excluding the rotational drive mechanism.
 6. The rotary drum type litter separating apparatus according to claim 2, further comprising a rotational drive mechanism provided on the peripheral surface of the cylindrical unit around a central portion in a height direction of the cylindrical unit; wherein the mesh part is detachably attached to a portion of an outer periphery of the cylindrical unit excluding the rotational drive mechanism.
 7. The rotary drum type litter separating apparatus according to claim 3, further comprising a rotational drive mechanism provided on the peripheral surface of the cylindrical unit around a central portion in a height direction of the cylindrical unit; wherein the mesh part is detachably attached to a portion of an outer periphery of the cylindrical unit excluding the rotational drive mechanism.
 8. The rotary drum type litter separating apparatus according claim 1, further comprising a support frame; wherein said cylinder unit is rotatably supported on said support frame.
 9. A litter separating apparatus comprising: a support frame; a cylindrical unit rotatably supported on said frame member, said cylindrical unit having a peripheral surface thereof formed in a mesh form; and a mesh part formed separately from the cylindrical unit, and arranged such that said mesh part wraps around the cylindrical unit, said mesh part being formed in a mesh form having a mesh size different from a mesh size of the peripheral surface of the cylindrical unit.
 10. The litter separating apparatus according to claim 9, wherein said cylindrical unit comprises a bottomed part which closes one end of the cylindrical unit, and a loading/unloading port which opens the other end of the cylindrical unit.
 11. The litter separating apparatus according to claim 9, wherein: said mesh part comprises a plurality of hooks provided on opposite end sides thereof; opposite end sides of the mesh part are connected to each other by using said hooks.
 12. The litter separating apparatus according to claim 9, wherein a mesh size of the mesh part is finer than a mesh size of the peripheral surface of the cylindrical unit.
 13. The litter separating apparatus according to claim 9, further comprising a rotational drive mechanism arranged substantially around a peripheral central portion of the cylindrical unit; wherein the mesh part is arranged around an outer periphery of the cylindrical unit excluding said peripheral central portion of the cylindrical unit.
 14. A litter separating apparatus, comprising a cylindrical unit having an outer periphery thereof formed in a mesh form; a blade arranged inside said cylindrical unit; and a mesh part formed in a mesh form and arranged around the outer periphery of the cylindrical unit; wherein said blade has a spiral shape.
 15. The litter separating apparatus according to claim 14, wherein said mesh part is formed separately from said cylindrical unit.
 16. The litter separating apparatus according to claim 14, wherein said blade includes a first flat portion; a first bent portion connected to the first flat portion; a second flat portion connected to the first bent portion; and a second bent portion connected to the second flat portion.
 17. The litter separating apparatus according to claim 16, wherein: said cylindrical unit comprises a bottomed part which closes one end of the cylindrical unit, and a loading/unloading port which opens the other end of the cylindrical unit; and said blade is arranged inside the cylindrical unit such that the first flat portion and the second bent portion of said blade are disposed on the loading/unloading port side and the bottomed part side, respectively.
 18. The litter separating apparatus according to claim 16, wherein said blade is configured such that the first flat portion and the second flat portion form an acute angle therebetween; and the second flat portion and a tangent line of the second bent portion at its tip also form an acute angle therebetween.
 19. The litter separating apparatus according to claim 16, further comprising another blade; wherein said blades are arranged symmetrically with respect to a rotation axis of the cylindrical unit, and are arranged obliquely with respect to a height direction of the cylindrical unit.
 20. The litter separating apparatus according to claim 16, wherein: said first bent portion is bent from the first flat portion to the second flat portion; and a length of the first flat portion and the first bent portion in a height direction of the cylindrical unit is less than a length of the second flat portion and the second bent portion. 